kern: Add initial ACPI impl

Signed-off-by: Ian Moffett <ian@osmora.org>

6 files changed, 273 insertions, 0 deletions

diff --git a/src/sys/acpi/acpi_init.c b/src/sys/acpi/acpi_init.c
new file mode 100644
index 0000000..76c582b
--- /dev/null
+++ b/src/sys/acpi/acpi_init.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/bootvars.h>
+#include <sys/panic.h>
+#include <sys/syslog.h>
+#include <acpi/acpi.h>
+#include <acpi/tables.h>
+#include <vm/vm.h>
+
+static size_t root_sdt_len = 0;
+static struct acpi_root_sdt *root_sdt = NULL;
+static uintptr_t rsdp_pa = 0;   /* [physical address] */
+
+size_t
+acpi_get_root_sdt_len(void)
+{
+    return root_sdt_len;
+}
+
+void *
+acpi_get_root_sdt(void)
+{
+    return root_sdt;
+}
+
+/*
+ * ACPI initialization
+ */
+int
+acpi_init(void)
+{
+    struct bootvars bootvars;
+    struct acpi_rsdp *rsdp;
+    int error;
+
+    error = bootvars_read(&bootvars, 0);
+    if (error < 0) {
+        panic("acpi: failed to read bootvars\n");
+    }
+
+    /* Fetch the RSDP */
+    rsdp = bootvars.rsdp;
+    rsdp_pa = VIRT_TO_PHYS(rsdp);
+
+    /* Fetch the root SDT */
+    if (rsdp->revision >= 2) {
+        root_sdt = PHYS_TO_VIRT(rsdp->xsdt_addr);
+        printf("acpi: using XSDT as root SDT\n");
+    } else {
+        root_sdt = PHYS_TO_VIRT(rsdp->rsdt_addr);
+        printf("acpi: using RSDT as root SDT\n");
+    }
+
+    if (acpi_checksum(&root_sdt->hdr) != 0) {
+        panic("root SDT checksum is invalid!\n");
+    }
+
+    root_sdt_len = (root_sdt->hdr.length - sizeof(root_sdt->hdr)) / 4;
+    return 0;
+}
diff --git a/src/sys/acpi/acpi_subr.c b/src/sys/acpi/acpi_subr.c
new file mode 100644
index 0000000..eab1f4f
--- /dev/null
+++ b/src/sys/acpi/acpi_subr.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <acpi/acpi.h>
+#include <vm/vm.h>
+#include <string.h>
+
+int
+acpi_checksum(struct acpi_header *hdr)
+{
+    uint8_t csum = 0;
+
+    for (int i = 0; i < hdr->length; ++i) {
+        csum += ((char *)hdr)[i];
+    }
+
+    return csum == 0 ? 0 : -1;
+}
+
+void *
+acpi_query(const char *query)
+{
+    struct acpi_header *hdr;
+    struct acpi_root_sdt *root_sdt;
+    size_t root_sdt_len, signature_len;
+
+    root_sdt = acpi_get_root_sdt();
+    root_sdt_len = acpi_get_root_sdt_len();
+    signature_len = sizeof(hdr->signature);
+
+    for (size_t i = 0; i < root_sdt_len; ++i) {
+        hdr = (struct acpi_header *)PHYS_TO_VIRT(root_sdt->tables[i]);
+
+        if (memcmp(hdr->signature, query, signature_len) == 0) {
+            return (void *)hdr;
+        }
+    }
+
+    return NULL;
+}
diff --git a/src/sys/include/acpi/acpi.h b/src/sys/include/acpi/acpi.h
new file mode 100644
index 0000000..e43d2cd
--- /dev/null
+++ b/src/sys/include/acpi/acpi.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MACHINE_ACPI_H_
+#define _MACHINE_ACPI_H_
+
+#include <sys/types.h>
+#include <acpi/tables.h>
+
+/*
+ * Perform an ACPI checksum on a specific ACPI
+ * header
+ *
+ * @hdr: Header to be verified
+ *
+ * Returns zero on success, otherwise a less than zero
+ * value if the checksum is invalid
+ */
+int acpi_checksum(struct acpi_header *hdr);
+
+/*
+ * Get the number of entries within the root system
+ * descriptor table
+ */
+size_t acpi_get_root_sdt_len(void);
+
+/*
+ * Get the root system descriptor table base
+ * address.
+ */
+void *acpi_get_root_sdt(void);
+
+/*
+ * Query for an ACPI table
+ *
+ * @query: Signature of table to query
+ *
+ * Returns virtual base address of table on success,
+ * otherwise NULL on failure.
+ */
+void *acpi_query(const char *query);
+
+/*
+ * Initialize the ACPI subsystem
+ *
+ * Returns zero on success, otherwise a less than zero
+ * value on failure.
+ */
+int acpi_init(void);
+
+#endif  /* !_MACHINE_ACPI_H_ */
diff --git a/src/sys/include/io/cons/screen.h b/src/sys/include/io/cons/screen.h
new file mode 100644
index 0000000..12bc3b5
--- /dev/null
+++ b/src/sys/include/io/cons/screen.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _CONSOLE_SCREEN_H_
+#define _CONSOLE_SCREEN_H_ 1
+
+/*
+ * Represents a console screen that can be written
+ * to and drawn on.
+ */
+struct conscr {
+};
+
+#endif  /* !_CONSOLE_SCREEN_H_ */
diff --git a/src/sys/os/Makefile b/src/sys/os/Makefile
index c5de3ed..158eab4 100644
--- a/src/sys/os/Makefile
+++ b/src/sys/os/Makefile
@@ -9,6 +9,7 @@ CFILES = $(shell find . -name "*.c")
 CFILES += $(shell find ../vm -name "*.c")
 CFILES += $(shell find ../lib -name "*.c")
 CFILES += $(shell find ../io -name "*.c")
+CFILES += $(shell find ../acpi -name "*.c")
 
 DEPS = $(CFILES:.c=.d)
 OBJECTS = $(CFILES:%.c=%.o)
diff --git a/src/sys/os/os_init.c b/src/sys/os/os_init.c
index 616aa84..2faf962 100644
--- a/src/sys/os/os_init.c
+++ b/src/sys/os/os_init.c
@@ -2,6 +2,7 @@
 #include <sys/panic.h>
 #include <sys/syslog.h>
 #include <sys/cpuvar.h>
+#include <acpi/acpi.h>
 #include <io/cons/cons.h>
 #include <vm/vm.h>
 
@@ -19,6 +20,7 @@ main(void)
 
     printf("booting l5 lunos v0.0.1...\n");
     vm_init();
+    acpi_init();
 
     panic("end of kernel reached\n");
     for (;;);